Method for realizing mid-consistency grinding in low-consistency device

Abstract

The invention discloses a method for realizing mid-consistency grinding in a low-consistency grinding device. In a slurry preparing stage, a slurry flowage modifier is added so that the slurry flowability is unchanged after increasing the grinding consistency to realize mid-consistency grinding in the low-consistency grinding device. The method comprises the specific steps as follows: placing paper pulp into a pulper for pulping, and adding a slurry flowage modifier inthe pulping process, wherein the use amount of the flowage modifier is 0.005-5 percent of that of oven dry stock; and grindingthe mid-consistency slurry of 6-8 percent after adding the slurry flowage modifier in the low-consistency grinding device for grinding. The method is simple and safe, and realizes mid-consistency grinding in the low-consistency grinding device without equipment investment; in addition, the manufactured slurry can be applied as ordinary slurry for improving the quality of paper.

Description

technical field [0001] The invention belongs to the field of pulping and papermaking, and in particular relates to a method for realizing medium-consistency (6%-8%) refining in low-consistency (concentration below 5%) equipment. The slurry prepared by the method can be directly used in papermaking. Background technique [0002] "Ten points for papermaking, seven points for beating", the importance of beating equipment is particularly important for the paper industry. The beating equipment has also developed rapidly in recent decades, from the early trough beater to the later conical refiner, cylindrical refiner and now widely used double-disc refiner; , Developed to continuous refining, while improving the quality of beating, it also takes into account the needs of actual mass production. In particular, in the late 1990s, with the implementation of high-speed and large-width paper machines in a series of factories such as Gold East Paper, the development of double-disk ref...

AI Technical Summary

Problems solved by technology

Therefore, its fluidity is better, so that some fibers are thrown out with less beating action or even without any beating action, while other fibers are excessively cut due to severe shearing by the grinding teeth of the grinding plate, and the quality of the obtained pulp after grinding is extremely high. Unevenness, which negatively affects the paper's apparent evenness, two-sidedness and physical strength of the paper

In order to improve this situation, some enterprises pursue a high beating degree to reduce the gap between the grinding discs. Although the uniformity of the slurry is improved from the results, it also leads to the severe cutting of the slurry and the fragmentation of miscellaneous cells, thereby reducing short The applicable quality of fiber pulp and the range of use of pulp affect the strength of the paper sheet and cause a large loss of pulp and high energy consumption for beating. The result is not worth the candle!

[0004] (2) Since the traditional double-disk mill is only suitable for low-consistency beating, the energy consumption of the effective beating applied to the fiber itself by the grinding plate is low, and the energy utilization rate is low. Most of the energy is consumed in mechanical friction loss and water ineffectiveness. Therefore, the unit energy consumption of low-consistency beating equipment for dry pulp is relatively high, and the equipment efficiency is low, which also objectively increases the copying cost of short-fiber pulp.

[0008] 2. Benefit impact

When changing to medium consistency refining equipment, it is necessary to stop the machine to replace the above equipment, which will affect the efficiency of paper making

[0009] 3. Impact on device stability

[0011] 1. The pulper cannot work

Generally, the low consistency system is equipped with a low consistency pulper, and its maximum pulping concentration is generally not more than 6%. If the concentration is raised to the range of medium consistency, the pulper will not work normally, and pulping and blockage will often occur. , and seriously affect the pulping effect

[0012] 2. The refiner cannot operate normally

In the low-consistency system, the maximum refining concentration that the refiner can withstand is generally not more than 6%. If the concentration is raised to the range of medium-consistency, the slurry cannot flow normally in the cutterhead due to the fluidity of the slurry. The phenomenon of slurry clogging the cutter head is becoming more and more serious, and may even cause the refiner to be stuck, unable to run, and the motor to burn out, etc.

[0013] 3. Pumping and pipelines cannot carry

However, in the case of medium concentration, due to the increase of slurry concentration, the fluidity of the slurry is significantly reduced, and the pipeline is blocked again, and the pumping cannot be realized.

[0014] In the low-consistency system, to achieve medium-consistency refining, it is necessary to overcome the problem that the fluidity of the guided pulp decreases after the concentration of the pulp is increased.

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